ZmPIN1-Mediated Auxin Transport Is Related to Cellular Differentiation during Maize Embryogenesis and Endosperm Development
ZmPIN1-Mediated Auxin Transport Is Related to Cellular Differentiation during Maize Embryogenesis and Endosperm Development
复制标题
DOI：
10.1104/pp.109.150193
复制
发表时间：
2010-03-01
期刊：
影响因子：
7.4
通讯作者：
Varotto, Serena
中科院分区：
文献类型：
--
作者：
Forestan, Cristian;Meda, Silvia;Varotto, Serena
为了研究单子叶植物胚胎发生和胚乳发育过程中 PINFORMED1 (PIN1) 介导的生长素运输的影响，在转录水平上确定了三个已鉴定的 ZmPIN1 基因的表达模式。在玉米（Zea mays）籽粒发育过程中也分析了相应蛋白质的定位。使用抗吲哚 3-乙酸 (IAA) 单克隆抗体来可视化 IAA 分布，并将 ZmPIN1 蛋白介导的生长素主动运输方向与不同发育阶段玉米籽粒中生长素的实际量相关联。双受精发生后不久，ZmPIN1 基因在胚乳中表达；然而，与其他组织不同，ZmPIN1 蛋白从未极性定位于胚乳细胞的质膜中。 ZmPIN1 转录物和蛋白也在发育中的胚胎中共定位，并且 ZmPIN1 蛋白从第一个发育阶段就极性定位于胚胎细胞质膜中，表明 ZmPIN1 介导的生长素通量的存在。生长素分布可视化表明，糊粉层、基底胚乳转移层和胚胎周围区域积累了游离的生长素，并且在籽粒母系合点中也有最大量。在胚胎发生过程中，极性生长素转运始终与胚胎组织的分化和胚胎器官的定义相关。根据这些报告以及对有缺陷的胚乳 B18 突变体和 N-1-萘基邻苯二甲酸处理的籽粒中组织分化和 IAA 分布的观察，提出了玉米籽粒发育过程中 ZmPIN1 介导的生长素转运和相关生长素通量的模型。讨论了该模型与先前针对拟南芥（Arabidopsis thaliana）提出的模型之间的共同特征。
To study the influence of PINFORMED1 (PIN1)-mediated auxin transport during embryogenesis and endosperm development in monocots, the expression pattern of the three identified ZmPIN1 genes was determined at the transcript level. Localization of the corresponding proteins was also analyzed during maize (Zea mays) kernel development. An anti-indole-3-acetic acid (IAA) monoclonal antibody was used to visualize IAA distribution and correlate the direction of auxin active transport, mediated by ZmPIN1 proteins, with the actual amount of auxin present in maize kernels at different developmental stages. ZmPIN1 genes are expressed in the endosperm soon after double fertilization occurs; however, unlike other tissues, the ZmPIN1 proteins were never polarly localized in the plasma membrane of endosperm cells. ZmPIN1 transcripts and proteins also colocalize in developing embryos, and the ZmPIN1 proteins are polarly localized in the embryo cell plasma membrane from the first developmental stages, indicating the existence of ZmPIN1-mediated auxin fluxes. Auxin distribution visualization indicates that the aleurone, the basal endosperm transfer layer, and the embryo-surrounding region accumulate free auxin, which also has a maximum in the kernel maternal chalaza. During embryogenesis, polar auxin transport always correlates with the differentiation of embryo tissues and the definition of the embryo organs. On the basis of these reports and of the observations on tissue differentiation and IAA distribution in defective endosperm-B18 mutant and in N-1-naphthylphthalamic acid-treated kernels, a model for ZmPIN1-mediated transport of auxin and the related auxin fluxes during maize kernel development is proposed. Common features between this model and the model previously proposed for Arabidopsis (Arabidopsis thaliana) are discussed.